Sanded insulator and method of making the same.



A. 0. AUSTIN".

SANDEO INSULATOR AND METHOD OF MAKING THE SAME.

' APPLICATION HLED MAY 29. 1916.

1,284,975. Patented Nov. 19,,5918.v

2 SHEETS-SHEET liii/$55.9.-

A. 0. AUSTIN. ANDED INSUIJ ATOR AND METHOD OF MAKING THE SAME.

APPLICATION HLIED MAY 29. I9I6.

I ir/vzmssa' Q UNITED STATES PATENT OFFICE.

ARTHUR O. AUSTIN, OF BARBERTON, OHIO, ASSIGNOR TO THE OHIO BRASSCOMPANY,

OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

,sammn INSULATOR AND METHOD or MAKING THE SAME.

To all whom it may concern.-

Be it known that I, ARTHUR a citizen of the United States, residing atBarberton, in the county of Summit and State of Ohio, have inventedcertain new and useful Improvements in Sanded Insulators and Methods ofMakin the Same, of which the following is a specification.

This invention relates to insulators in which one or more of the partshave connected surfaces which are roughened or sanded to provide meansfor cementing the parts together and at the same time permitting greaterresilience between them, and to the method of uniting or connecting suchinsulator parts so constructed. The invention consists in the novelmethod employed in connecting the parts and forming the insulators. andin the novel contraction, combination and arrangement of the severalparts.

0. AUsTIN,

In the drawings, Figure 1 is a view, partly.

- shell coated with yielding material; Fig. 4

shows the adjacent portion of the insulating member so coated; Figs. 5and 6 are detail views showing projecting particles attached to theinsulating member; Fig. 7 is a view, partly in section, of a differentform embracing the method and construction of my invention; Fig. 8 is anenlarged view of a portion of the construction shown in Fig. 7 Fig. 9 isan enlarged detail similar to Fig. 8, in which the sanded surfaces arecontinued between the parts; Fig. 10 is an enlarged detail similar toFig. 8 with anelastic subtance interposed between the insulatorelements, and Fig. 11 is a detail view similar to Fig. 8 embodying apreviousl used method and construction.

In insulators which consist of a number of parts, either of similar ordifferent materials, it is customary to unite the several parts by means'of cement. The surfaces which are so connected may be knurled orgrooved for affording more anchoring surface for the cement and therebyconnecting the parts more rigidly together, but if the parts are toorigidly connected they may be lpeclflcation of Letters Patent.Application filed May 29, 1916. Serial No. 100,481.

Patented N 0v. 19, 1 918.

conditions which impair rather than improve the insulators. The unglazedsurfaces provided with grooves, or plain, may give fairly satisfactoryresults but there are certain conditions which it is desirable to securein insulators which can be better obtained if the surfaces are coveredwith glaze, not only where they are exposed to the weather but alsowhere they are in contact with cement. Cement, however, does not adherereadily to a glazed surface on account of its extreme glassy condition,therefore to glaze the surface to be cemented still maintaining thegrooves in the surface, as indicated in Fig. 11, would give desirablepropertiesin the porcelain, namely, increased electrical resistance, butit would produce a joint mechanically weak ,which would soon break apartor loosen up on account of the cement not adhering to the surface.

To overcome this mechanical and physical weakness and to secure theproperties which are desired in an insulator, it is found possible tocoat the surfaces of insulating material to be connected before theinsulatin member is fired in the kiln with material which will produce aglazed surface, and while this coating is still wet to sprinkle thereonsand or crushed material of substantially the same substance as that ofthe insulating member, which has or has not 35 been vitrified, but whichwill adhere to this coating on account of it being in a moist and stickycondition when first applied. Crushed unvitrified clay is preferable forthe reason that if of the same composition as the body of the insulatingmember it will then have the'same coefficient of expansion andcontraction in firing as the insulating member; itself since the two arevitrified at the same time, and therefore, there will be no tendency iber itself is practically covered with glaze,

thus giving a surface which adds to the electrical resistance andprevents the absorption of moisture but. leaves the points of the '105projection or particles projecting above the .glaze and'practically freeof glaze at the outer ends, the bases and sides of the parti theroughened particles and the base of the projections. This leaves the'end of the projections free to extend into the connecting cementpractically free of the coating material so that they will engage thecement or-binding material between the parts. Since these projectionsare of considerably smaller area than the main body of the insulatingmember a force or. straln transmitted between the insulator parts orbetween a part and the cement will be concentrated in the projections.The projections being of elastic material and having a smaller sectionthan the main body, the stress or strain tending toward disruption willbe in inverse proportion to their cross sectional area and directlyproportional to their length. It isevident then that if the projectionsare of sufficient length and of small enough cross section the internalstrain or yielding stress between the main parts can be almost entirelytaken up by these projections keeping .down the stress in the maininsulating members.

, It is evident that there are a number of ways 'of obtaining thisresult, such as providing the members which are to be assembled togetherwith ribs or a knurled or roughened surface. Where-metal parts areassembled with aninsulating member they may be prepared and treated thesame way. ,A substitute for producing a rough surface of insulatingmaterial, such as porcelain or cement, as above described, is to roughenthe surface of the insulating member before firin by means of a propertool, such as a knur ing wheel, and as this surface is then glazed atthe time of firing, the glaze produces a surface which is non-absorbentto moisture and has a higher resistance.

. As before stated, it is found that whenthe insulator parts throughprojections they offer a yielding r-ip upon the cement even though theproections may of-themselves be very brittle. This yielding grip isquite an advantage on account of permitting ex ansion and contractionofthe cemented oint, thereby assisting to reduce strains in theassembled insulators through contraction and expansion from temperaturechanges and it has been found'that this yielding or elastic conditioncan be further increased by treating such nded or roughened surfaceswith a semihard orelastic compound such as paraffin wax, or a quickdrying elastic varnish, be-

fore the insulator parts are connected. This are cemented togethersemi-hard or elastic material is applied to the sanded surfaces andpartially fills the recesses between the small projections by capillaryattraction on such surfaces, as indicated in some of the detaildrawings. This partial filling of the spaces between the projectionsstill leaves the 'points or tips of the projections extending'beyond thesemishown in the drawings.

For example, a portlon of an insulating member 11 in Fig. 5 is coatedwith a rather thick coating of glaze 9 in which particles connectingcement. If the glaze 9 is a thin coating, as shown in Fig. 6, theparticles 13 will be less firmly held at the base, and will therefore bemore resilient, the elastic coat- 1ng 15 then fillin the hollow betweenthe pro ections as befbre. Quite a wide variation can be produced bychanging the sizes of the particles. the thickness of the coating ofglaze and the yielding material.

A surface thus prepared adds to the electr cal resistance, decreases themoisture absorbing property of the insulating material,

distributes the strain between the parts uniformly over the preparedsurface, and produces a contact surface which is elastic or yielding ascompared with the old method of connecting insulator parts directly withcement, as indicated in Fig. 7

If desired, this prepared surface with the sanded or roughenedconstruction can be extended entirely over the surfaces in contact withthe cement, as indicated in Fig. 9, but there is no particular advantagein having more than'the vertical sides of the insulator surfaces thusprepared and to sand the portions indicated with the reference numerals16 and 17 in Fig. 8 would not materially increase the holdin effectbetween the two parts. Therefore, 1n order to preserve the elasticor'yielding properties the semi-hard or elastic materlal is extendedover those surfaces whichv have no substantial gripping effect but toomit the sanded or roughened condition therefrom.

Referring now to Figs. 7 and 8, an insulator composed of two insulatingparts 10 and 11 is formed with particles 12 and 13 constituting sandedor roughened surfaces which have been vitrified on the surfaces of theinsulating parts and are to all intents and purposes integral parts ofthe insulathard or elastic-filling material, as clearly 50 jacentinsulating material, thereby making ing members. These parts are securedto.-. gether by cement 14 which engages the extremities-of projections12 and 13, as shown more clearlyin Fig. 8. The semi-hard or elasticmaterial which fills the space between the projections at their bases isdesignated by the reference numeral 17 and the sharp points of theparticles which. extend beyond the elastic filling material areindicated by the reference numeral16, for example in Figs. 8 and 10.

In some instances it is found advantageous to even increase the elasticcondition the parts such as indicated etween the surfaces which receivea radial strain under expansion andcontraction of by the coated surfaceslfi' and 17in Fig. 8. This is done by inserting a disk 18 of yielding orelastic material, as shown in 10, or a heavy elastic. coating 19 asshown in Figs. 1 and 2, the disk18 being of yielding or elastic materialsuch as felt, paper and the like.

This method of uniting insulator parts is not confined to use withinsulators which consist only of insulating members but is equallyapplicable to-a structure, as shown in Fig. l, in which a metal cap 19'is cemented to an insulating member 20 and the, latter to a metalsuspension pin 21. In this case the insulating member has a projctingboss 22 with a recess in whichthe' pin 21 is inserted, the inner andouter side surfaces of the boss being formed with sanded projections, aspreviously described,

and the metal cap and pin being formed with retaining grooves ordepressions for anchoring the cement 14 thereto. Both of the cementedconnections between the insulating member and the metallic members havethe advantages of elasticity and resilience, as above set forth, toprovide for the relative yielding due to expansion and contraction.

In addition, a ring 23 also of elastic material, such as felt, paper andthe like, is interposed between the edge of the cap 19' andthe body orflange of the insulating member 20 for-allowing the expansion andcontraction which may take place between the lower edge of the metal capand the ada yielding contact between them and pre venting the surface ofthe insulating member from being checked or cracked due to the hardnessof the metal, andalso for spacin I the edge of the cap and the flangeapart.

Tnstead of providing a pad or gasket 23 the lower edge of the metal cap19, as

. shown in Fig. 3, may be provided with a coating 25of yielding materialwhich will effectually space the insulating member 20 and cap apart; orthe adjacent surface of the insulating member may be. painted or coatedwith elastic material 26, as shown in Fig. 4, which serves the samepurpose. In

either case, the formation of a bead or rim 14K of cement on the outsideof the edge of the cap, does not form arigid strut between the cap andinsulating'member, as the yielding material 25 and 26 is also'betweenthem. The metal cap 19 may also be made thin at its upper portion 24 toprovide a yieldable portion which will burst under pressure due toexpansion or contraction, thus, relieving the pressure, without entirelyseparating the insulating member from the metal cap .and causing amechanical break-down.

In Fig. 10 is shown a construction in which the insulator parts areformed with a roughened surface instead of sanding the glazed surfaces,asabove explained. In this case the glaze may be left oif of theroughened parts and merely an elastic coating 15 supplied, which asbefore set forth, collects at the bases of the roughened projections 16leaving the points free to engage the cement 14:. c

The advantage of insulators constructed in accordance with thisinvention is that the projections formed are more or less resilientwhich tends to relieve the main insulating members of stress which maybe set up between them, the projections thus distribof a considerablecontrol, in the elasticity,

it holds the parts together firmly, and is cheaply made. By regulatingthe size of the projecting points, their number and the a coatingmaterial 1s readily seen that a wide range in elasticity may be providedfor stresses applied to the point in either direc tion. Joints may bemade by this method such that there will be no looseness between theparts but still they will have sufficient elasticity or give so as torelieve internal stresses or those due to applied load. Because of thisgreater elasticity insulators constructed in accordance with theseprinciples are able to withstand the stresses due to expansion andcontraction with less frequent breakage.

What I claim is: I

1. The process of making insulators hava ing a plurality of parts, whichconsists in coating adjacent corresponding surfaces with material whichproduces a glaze when the 1 the said coating before firing uneven par-'insulator parts are vitrified, in applying to vticles of the samematerial as that of which ing adjacent corresponding surfaces with amaterial which-will produce an adhering coating of glaze when theinsulating, parts are fired; in applying to the coatingbefore firinguneven particles which will withstand the firing heat withoutdistorting, and will adhere to the insulator surface and project abovethe coating, in firing the parts thus coated so that the, projectingparticles will be uncoated with glaze; in coating the surface thusprepared with a yielding material and in applying cement between thesaid corresponding surfaces on top of the yielding coating to form arigid connection between the parts and at the same time permitting ofexpansion and contraction thereof due to changes in temperature.

3. An insulator consisting of a plurality of parts having cooperatingcementing surfaces, one or more of the surfaces having thereon anunderlying glaze from which a there are projections; a coating of yielding material reposing on the cementing surfaces and held in the spacesbetween the projections; and cement between the roughened surfaces ofthe parts to be united so that there will be a rigid connection but ofsufficient resilience to permit of expansion and contraction withoutbreaking the insulator parts.

4. An insulator consisting of a plurality of parts with correspondingcementing surfaces, the surfaces provided with a multiplicity of uneven,unglazed projections extending above a coating of glaze on the cementingsurface, and by which the projections are made to form a substantiallyintegral part of the insulator; a coating of yielding material reposingon the cementing surfaces but from which the projection extremities aresubstantially free; a pad of yielding material interposed betweenadjacent corresponding surfaces not roughened; and cement interposedbetween the roughened cementing urfaces for rigidly connecting the proections so that a yielding action of the insulator parts may be had dueto the expansion and contraction in use.

5. An insulator consisting of a plurality of parts with correspondingcementing surfaces, the surfaces provided with a multi- H plicity ofuneven, unglazed particles having projections extending above a coatingof glaze on the cementing surface and by which the projections are madeto form a substanexpansion and contraction in use.

6. An insulator consisting'of a plurality of parts, one or more of theparts being composed of an insulating material, the parts being providedwith corresponding cementing surfaces and the insulating member havingits cementing surfaces provided with uneven unglazed projectionsextending above a glazed surface and forming a substantially integralpart of the insulator, a layer of yielding material reposing on theprojections, and cement rigidly connecting the projections of one partwith the surfaceof the adjacent part so that a yielding action of theparts may be had in case of expansion and contraction in use.

7. An insulator comprising a plurality of parts, each of which has aglazed cementing surface one or more of which has projections whichextend above the glaze, a coating of yielding material for saidprojections, and cement interposed between the cementing surfaces on topof the elastic coating and engaging said projections to form a rigidconnection between the parts which permits of expansion and contractionbeing taken up largely in the rigid connection so as to reduce stress inthe insulator parts proper due to expansion and contraction.

8. An insulator consisting of a number of parts provided withcorresponding surfaces for uniting the various parts, the correspondingsurfaces provided with uneven particles having projections extendingabove and integrally attached to the surface by a layer of glaze,yielding material interposed between the surfaces of the parts notroughened, and a layer of cement connecting the projections on theroughened surface,thereby producing a yielding joint between the partsin case of expansion and contraction in use.

9. An insulator consisting of a numberof parts one or more of the partshaving connectinc. surfaces provided with a plurality of pointedprojections, a layer of yielding material reposing on the roughenedconnect- 12 mg surfaces at the base of the projections, and cementconnecting the projections above the yielding coating to carry' thestresses between the insulator parts by the projections whichextend intothe cement.

10. An insulatorcomposed of a plurality of parts having cooperatingcementing sur faces, cement positioned between the cooperatlng cementingparts and one or more of the parts composed of a vitreous insulating 130material, means distinct from the parts themselves projecting from thecementing ment between the connecting surfaces in which the projectionsare embedded so that stresses between the parts will be carried by theprojections, thus relieving the insulating partsthemselves of internalstrain.

12. An insulator consisting of a plurality of members, particles thereonwith pointed projections, and cement uniting the members by connectingthe outer ends of the projections thereby concentratingthe strainbetween the parts in the projections which are of comparatively smallcross section, and relieving the main insulating members of stress dueto uneven expansion or contraction of-the parts of material used in theassembly.

13. An insulator comprising a plurality of parts, one or more of whichare composed of insulating material, means on the parts w whereby theymay be assembled into a single unit, the means comprising a partly rigidand partly yielding bearing surface whereby the stresses in theinsulator members due to changes in temperature will be minimized andthe stresses will be concentrated in the rigid bearin surface.

14:. An insulator consisting of a plurality of parts having connectingsurfaces which are roughened by projections, a coating of yieldingmaterial reposing on a part of the rou hened surface the remainln art of9 b the surface being practically free of yielding material, and afastening cement engaging the part of the projections free of yieldingmaterial and uniting the insulator parts, thus minimizin the stressestransmitted to' the insulating members proper due to changes intemperature.

15. An insulator comprising a plurality of parts having roughenedprojections on the surface to be attached to a part of the roughenedsurface leaving theouter extremities of the roughened projections freefrom such material, and cement connecting the arts by engaging theouterextremities of t e rough projections thereby minimizing thestresses transmitted from one insulating member to the other, andconcentrating the strain in the connected projections.

16. An insulator of connected insulating parts, projections on theconnecting surfaces, a yielding material reposing between the proections and parprojections, the points of joined, a yieldingmaterialconsisting of a number tially covering the space therebetween,and cement interposed between the parts and into which the projectionsextend.

' 17. An insulator consisting of a number of parts, each part having acementlng surface with projections therefrom, a yielding materialreposing in the spaces between the the projections belng free ofyielding material, and cement dlsposed between the points of theprojections not coated, thereby reduclng the actual contact surfacebetween the parts and concentrating the strain in the projections.

18. An insulator consisting of a number 7 of separate parts each havinga connecting surface comprising particles with pointed projectionsextending from the body of the insulator and held thereto by av vitreouscoating and forming a substantial continuation thereof, the crosssection of the projections decreasing toward the end, and a cementinterposed between lthe connected parts and between the extremities ofsuch projections for concentrating the stress or strain due to expansionand contraction in the projections between the parts themselves.

19. An insulator consisting of a plurality of separate connected partshaving cooperating connection surfaces each formed with projectionssubstantially integral therewith decreasing their ends, ayieldingcoating applied to the projections and substantially filling thespaces at the bases thereof between the projections, leaving theextremities free of such' material, and a connecting cement interposedbetween the parts and contacting with that portion of each projectionwhich extends above the yielding coating applied thereto.

20. An insulator comprising a plurality of parts, each formed with aglazed connecting surface and each having corresponding roughenedsurfaces formed by applying particles of substantially the same materialas the insulator parts to the glazed surface before firing, and aconnecting cement inter= .posed between the parts forming a substananelastic coating applied to the projections and caused by caplllaryattraction to collect at the bases of the projections, leaving theextremitles of the projections free from such in cross section toward a"plicity of small projections composed of the of nested parts cementedtogether, one or more of the nested parts composed of a vitreousinsulating material having its cementing surfaces formed with amultisame material as the insulating members and held to the cementingsurface of the insulating member by a vitreous glaze.

23. An insulator consisting of a plurality A of parts united by a cementinterposed between adjacent surfaces and one of the parts being composedof an .insulating'm'aterial having its cementing surfaces formed with amultiplicity of projections composed of a material similar to that ofthe insulating member and attached to the cementing surfaces ofthe-insulating member by a vitreous glaze.

24. An insulator consisting of a plurality of parts united by a cementinterposed between surfaces and one of the parts being composed of aninsulating material having its cementing surfaces formed with amultiplicity of projections, and a yielding coating applied to thecementing surfaces and resting at the base of the projections leavingthe larger portionof the projections free of the yielding material, thefree part of the projections being embedded in the cement.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses on the 26th day of May, A. D.1916.

I ARTHUR O. AUSTIN.

Witnesses A: J. CRANE, K. WV. WONNELL.

